Use more sensible label for non-labeled procs

spec/expectations/block_expectation_partial_spec.cr

@@ -30,10 +30,10 @@ describe Spectator::Expectations::BlockExpectationPartial do
     end
 
     context "when omitted" do
-      it "contains a stringified version of #actual" do
+      it "contains \"proc\"" do
         actual = ->{ 777 }
         partial = Spectator::Expectations::BlockExpectationPartial.new(actual, __FILE__, __LINE__)
-        partial.label.should eq(actual.to_s)
+        partial.label.should match(/proc/i)
       end
     end
   end

src/spectator/expectations/block_expectation_partial.cr

@@ -19,7 +19,7 @@ module Spectator::Expectations
     # The label is generated by calling to_s on the block.
     # The block is stored for later use.
     protected def initialize(@block : Proc(ReturnType), source_file, source_line)
-      super(@block.to_s, source_file, source_line)
+      super("<Proc>", source_file, source_line)
     end
   end
 end